Digital x-ray detectors have been changing classical radiography, angiography and cardioangiography for some years. Various technologies for digital x-ray detection have in some cases been in use for a long time or are just about to become commercially available. Among these digital technologies are image intensifier camera systems based on television or CCD cameras, storage film systems with an integrated or external readout unit, selenium-based detectors with electrostatic readout, and solid-state detectors with active readout matrices with direct or indirect conversion of the x-ray radiation.
In contrast to classical radiography operating with x-ray films, in digital x-ray apparatuses the x-ray image exists in electronic form, in other words in the form of image data. This enables the x-ray image to be refined by electronic image processing before display on a screen, for example in order to make an organ to be examined or a sought pathological finding particularly well visible in the medical application. Prevalent methods of digital image processing include the per-pixel application of characteristic lines for gray-scale-dependent color or brightness modification of the x-ray image, filter operations such as the application of a low-pass, high-pass or median filter, frequency-band-dependent filtering, contrast or brightness operations (also designated as windowing), and the like.
The abundance of available setting parameters normally allows the same raw image supplied by the x-ray detector to be refined into final images that can significantly differ with regard to their optical appearance. However, the expected image appearance and the appearance that is believed to be optimal generally differ from radiologist to radiologist. This leads to individual adjustments with regard to the image refining normally having to be effected in the installation of an x-ray system, in order to adapt the final images generated by the x-ray apparatus to the taste or the precedent of the x-ray department, or even to the individual radiologist.
This adjustment process must normally be performed in close collaboration between the technicians carrying out the installation and the intended users, in other words radiologists or other application specialists, particularly as the setting of the abstract parameters presupposes detailed knowledge of the image refining technology, which cannot be assumed to be the case in respect of the application specialists who are as a rule medically trained. Considerable resource requirements in terms of personnel and time are therefore associated with installation of the x-ray apparatus. This is due particularly to different sets of image processing parameters having to be created for each organ (for example thorax, hip, abdomen, skull, extremities, etc.) to be acquired by the x-ray apparatus, each projection (lateral, aperior-posterior, oblique, etc.), and possibly different generator settings (voltage, current, filtering, dose).
A method for the selection of equipment parameters for an x-ray device, such as tube voltage and tube current, is known from US 2003/0108154 A1. For selection of the equipment parameters, a sample x-ray image preselected in accordance with a user-defined parameter model is displayed to a user, which simulates an image impression of an x-ray image such as is to be expected when setting the predefined equipment parameters on the x-ray device. When a sample image is selected by the user, the assigned equipment parameters are in so doing set on the x-ray device.